what did you do to your motorized bicycle today?

Discussion in 'Motorized Bicycle General Discussion' started by Skarrd, Oct 25, 2010.

  1. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    1
    Re: what did you do to your motor bike today?


    Be sure and check the lower con rod bearing and make sure it is not missing rollers, this is what happend to my first engine that did exactly what you just described yours did.....

    Mine seized up on me, I was able to get it unseized and then I thought it might be ok, I put it on another bike an it started and seemed to run fine, I took of one day on a 8 or 9 mile trip and on the way back about 200 yards form my house itjust quit and wizzed down to nothing, I could tell it had lost all compression....so I knew it wasn't a good thing that just happened, I pulled the jug and I had a ring broke, deep score it piston, deep score in cylinder wall, large chunk busted out of transfer port and then after checking things closer I realized that I was missing one or 2 needle bearing on the crank because there was way too much space in between the ones that were left and I could see that they tried to turn at an angle on the crank instead of sitting straight on the crank journal.

    This is when I got a used crank form someone and rebuilt that engine and it ran very good until that used crank petered out on me and ate into the case on the clutch side allowing the mag rotor to eat into the case on it's side and destroy the crank seal.

    Check that lower end out very good or you may be rebuilding another grenade.......

    best wishes to ya

    Peace
     
  2. chrisme

    chrisme New Member

    Joined:
    May 30, 2009
    Messages:
    423
    Likes Received:
    0
    Re: what did you do to your motor bike today?

    ^ sound advise. I too was going to rebuild a top end after a piston ate itself, and everything involved.

    But the bottom end was totally hosed. Tipped it upside down and needles fell out...
     
  3. Skarrd

    Skarrd Member

    Joined:
    Oct 13, 2010
    Messages:
    499
    Likes Received:
    1
    Re: what did you do to your motor bike today?

    thinking now i'm gonna swap the mag coil over to the grubee bottom end when i rebuild it. that way i'll have time to pull this one apart and carefully inspect everything in it.
     
  4. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    1
    Re: what did you do to your motor bike today?

    Very good idea.....I would hate to see you put all that money and trouble in that lower just to hammer it again like I did mine..........

    I was just being a cheap skate noob when I did mine, but I learned a valuable lesson from that mistake.
     
  5. Skarrd

    Skarrd Member

    Joined:
    Oct 13, 2010
    Messages:
    499
    Likes Received:
    1
    Re: what did you do to your motor bike today?

    ouch man, that sucks.

    was almost tempted to get some puch parts to replace it with c:
     
  6. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    1
    Re: what did you do to your motor bike today?

    Yeah, I really should have known better with all the small engine I've built up and repaired over the last 30 years, I wasn't sure what my problem was at the time and thought since the engine came loose I would just go ahead and give it another try...........it lasted about 10 miles and bam ther she went and it was done, that lower con rod bearing was faulty from the factory and it cost me that engine, only thing I saved was the case and clutch parts, then I rebuilt it with a used crankshaft that looked to be in very good shape and it failed again after only 420 miles, engine was still running but the crank shifted and ate up the case under the mag rotor which also destroyed the crank seal which caused it to rev out of control and run like it had cruise control...it didnt run long this way and the jug, piston and rings are all still in good shape, so I'm gonna order a new lower engine assy. from BGF and just put the jug & piston over on it and after a short run in period for the lower end, I should have myself another good engine........if the lower I get is a good one.!

    Peace
     
    #1406 mapbike, May 27, 2011
    Last edited: May 27, 2011
  7. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    1
    Re: what did you do to your motor bike today?

    Just ordered that new lower end and a few other parts from LEB/BGF I have a bike I just got a week or so agao that this engine will go on with a 32T sprocket, it will have a sorta board track racer look when I'm done, won't be fancy to start with and may never be real fancy but I hope it will make a nice riding bike that will cruise real nice at around 35MPH, I may give that reversed jug a try on this one, not for sure on that one yet, but I might...... I know I will be doing some mods to this engine that I havent done to the others yet just to see if I can squeeze a bit more power out of it for that 32T sprocket.

    Peace
     

    Attached Files:

    #1407 mapbike, May 27, 2011
    Last edited: May 27, 2011
  8. WildAlaskan

    WildAlaskan New Member

    Joined:
    Sep 30, 2010
    Messages:
    581
    Likes Received:
    0
    Re: what did you do to your motor bike today?

    it was so hot out today i had to go for a 8 mile ride to cool off. a woppin 72 degrees felt like i was in an oven
     
  9. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    1
    Re: what did you do to your motor bike today?

    You would just love our Texas weather then, over 100 here today and thats in the shade.

    I have a daughter -in - law and two grandbabies that live in the Fairbanks area so I guess they are experiencing the heat wave there too..LOL!
     
  10. Dan

    Dan Staff
    Staff Member

    Joined:
    May 25, 2008
    Messages:
    12,641
    Likes Received:
    62
    Re: what did you do to your motor bike today?

    LOL WA. I read th 1st 5 words and thought; "wut, got up to 70?"

    80 and muggy today here after the snowiest winter I have seen in CT. It just rained for 11 st8 days and we got 'skeeters bitting skeeter as we 2 legged folks are running out of blood for em. As soon as I get done mowing/fixing mowers, I am building about 50 bird houses and one big butt bat house, snork. Only thing I got to do with my MB is move it out of the way this week
     
  11. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    1
    Re: what did you do to your motor bike today?

    Hey Dan send those skeeter my way and I'll send them back with 3-4 more on them.......we are in the same boat down here where I live, and we haven't had much rain at all.......I just went and bought 5 dozen bass Minnows today and put them in a stock pond thats about 50 yards from my house, I'm hoping they will eat some of those skeeter larva.......
     
  12. Dan

    Dan Staff
    Staff Member

    Joined:
    May 25, 2008
    Messages:
    12,641
    Likes Received:
    62
    Re: what did you do to your motor bike today?

    OH Man Map! I didn't think of that! At the end of our property, is a marsh that is the end of a large pond or very small lake. Thank you! Like spammers, kill em young and be bothered less.

    Ya got me thinking 20 or 30 feeder gold fish. Them things could survive a nuc war. The fish go quick here. Lots of geese and swan. (Or as i like to call em, large killer ducks.) They will chase a large dawg or a very kind Carol. They run from me. I go for their necks. LOL, freaks em out. Har, lol. Think I sould get an air horn.


    Just realized my 3rd and doner parts mower has a really cool gas tank. Want to do a pusher MB and would work great.
     
    #1412 Dan, May 27, 2011
    Last edited: May 27, 2011
  13. retromike3

    retromike3 New Member

    Joined:
    Jan 9, 2009
    Messages:
    148
    Likes Received:
    0
    Re: what did you do to your motor bike today?

    riding over the hill today when I noticed that the button had rattled off my clutch lever. I was used to hitting the clutch and then being able to use the front brake. No such luck on the way into town and the way back home. all I had was the rear brake and my hand got a bit worn out by having to keep that clutch on at stop lights and especially when I was going downhill.

    So when I got home I dug the new clutch lever that came with my spare engine. Lucky for me I didn't just buy a new motor for a spare. I just installed it and I replaced the grip on that side because it was ripped a bit. I now have a new grip and a new lever I will find out how well they work tomorrow.

    mike.
     
  14. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    1
    Re: what did you do to your motor bike today?

    Yeah I dont like those geese and never been around a swan, but around these parts if something like that gets after me and causes any trouble they are very likely to come down with a serious case of lead poisoning if you know what I mean...LOL!

    I just do what I gotta do and let the good Lord sort-em out...LOL

    Now on the pusher subject you mentioned, that is something on my list as well, I have several ideas and dont know which one to go with for sure, I'll probably go with quick and easy for now but later I have some more labor intense things in mind, I'm just shade tree mechanicing most of my stuff for now but when I get set up the way I want with a good roomy work shop then I will tangle with soemn of those more complicated ideas.

    What size engine are you pkanning to use on yours Dan?
     
  15. Dan

    Dan Staff
    Staff Member

    Joined:
    May 25, 2008
    Messages:
    12,641
    Likes Received:
    62
    Re: what did you do to your motor bike today?

    LOL Map Buddy! When I was typing that kept thinking you were gonna advise scatter gun. Would be 6 cops and the FD here in 3.7 mins and I would be on the ground with HLS and a PETA rep asking me why I "did it"

    Pusher engine size. CT allows for 5HP! I got a comet torque converter still in the box. Wut I am thunking is gokart wheel and a 90 or 79 cc hf engine but would like to use a full 5HP. Thinking hang the weight lower then the axle so the engine rights it self. OR, go with a kids bike wheel so as to lower the center. Work like a pendulum. As long as the weight of the engine is below the line between the drive axle and where it pushes the bike, it stays upright.

    dunno and open to thoughts
     
    #1415 Dan, May 27, 2011
    Last edited: May 27, 2011
  16. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    1
    Re: what did you do to your motor bike today?

    Yep Remington 870 ........ go ahead geese.....make my day!


    Yeah I've got two of the HF 2.5 HP engines I just bought last week, and I have 2 of the GX200 clones, I have thought of the bike wheel also, I would use a 20" wheel because I might go with a rag joint for the sprocket mount and I checked a 16" wheel I have and the rag joint wont work on it because it's out of alignment with the spokes.

    I say get one of those 50 or 60T rag joint and sprocket kits from BGF and then with that Torque-a-verter you would have a pretty awesome set up, or at least I think so, this is the exact setup I have planned for what would be a very simple and quick build, I have a couple of the heavy duty BMX 20' wheels I've had for years that have huge spokes in them so I think they would work great for that project when I get the time for it.

    I have 2 of the Torque-a-verters on a couple of old gokarts that are still in good shape, I think they will work great if used on a 5hp or larger engine, but I'm not sure they would work to well on that tiny 2.5 HP HF engine, it takes a good bit of power to drive that converter set up, I dont think that little engine would ever get it out of low range, but I could be wrong.

    Another thing is that the Torque-a-Verters are designed for an engine with a 3/4" output shaft and the small engines have a 5/8" shaft, that would be another hurdle.

    Just get you a 6.5 clone from HF and repaint the tank and shroud an no one will ever know what it is, heck make you up a sticker that says 5HP and put it on the shroud, no one would ever know the difference.
     
    #1416 mapbike, May 27, 2011
    Last edited: May 27, 2011
  17. Mike B

    Mike B New Member

    Joined:
    Mar 23, 2011
    Messages:
    2,256
    Likes Received:
    2
    Re: what did you do to your motor bike today?

    8 mile ride for some errands. No problems - :)

    Guy on a mountain bike waiting at a light says "I need one of those", "that's the look", "Where did you get it"

    I say "yeah they rock" "thanks" "internet, you have to build it yourself"

    I have not seen one in town yet, but the way things are going every time I ride, I don't think it will be too long before I do.
     
  18. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    1
    Re: what did you do to your motor bike today?

    Well I shaved a New (woo woo! CHROME) slant head down and rejetted a different carb I put on the Kulana, I had ordered the new head from BGF because I wanted to replace the low compression straight plug head that was on that engine.

    After replacing the head and rejetting the carb I got 41MPH out of it, but I think bumping the compression up on that older engine over stressed the wrist pin bearing because I have a jittery sounding rattle on top of the engine now, I was a little leary of bumping the compression up that much on the older engine and I guess my apprehension was warranted now that it has a rattle on top, it ran good at first but after about a 7-8 mile round trip I noticed the rattle starting up on the way back home and it had gotten worse by the time I got here.

    So, I just got done ordering another top bearing along with a new wrist pin, I also ordered a new jug and piston & rings just in case I find another problem when I get into it, I know the noise is right up top so hopefully only need the top bearing replaced.

    wish me good luck on it, just an old engine that has lots of very hard miles on it, I got this engine used and it looked like it had been abused so it was needing a bit of TLC anyway, so I'll get-er freshened up a bit and hope for many more miles of good service out of-er.


    the pics show the difference in the combustion chambers old verses new that I put on engine compression is really bumped up now.

    scratg



    Peace
     

    Attached Files:

    #1418 mapbike, May 28, 2011
    Last edited: May 28, 2011
  19. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    1
  20. GearNut

    GearNut Active Member

    Joined:
    Aug 19, 2009
    Messages:
    5,105
    Likes Received:
    3
    Re: what did you do to your motor bike today?

    Got a little bit more done on my custom exhaust. Had to re think the rear mount. Sliced and diced 2 rear drop outs from a doner bike to make one that will be better off than my original idea. I only have a few hours a day to work on it. Slow and steady wins the race, eh? My welding skills are showing their rustyness [sic]too.
     

Share This Page